Semiconductor components, such as power MOSFETs or power IGBTs, for example, are increasingly being used as switching elements for switching electrical loads. Power MOSFETs or power IGBTs are voltage-controlled components which are turned on or turned off depending on a drive voltage present at a drive connection (gate connection). The drive voltage can be generated by a drive circuit depending on a switching signal, which is e.g., a logic signal.
There are circuit applications in which the switching signal and the drive voltage are signals and voltages, respectively, which relate to different electrical reference potentials. This is the case, for example, when the semiconductor switching element is used as a high-side switch. In such an application, the reference potential for the drive voltage, which potential corresponds to the electrical potential at one of the load path connections of the semiconductor switching element, can change depending on the switching state of the semiconductor switching element. A drive voltage with such a changing reference potential can be generated using bootstrap circuits, level shifters or else electrical decoupling elements such as optocouplers or transformers, for example.
In addition to information about the switching signal, generation the drive voltage additionally requires a supply voltage from which the drive voltage is generated depending on the switching signal.